In the Columns tab of the editor, it's possible to create different types of columns, such as Text, Enum List, and Ref, among others. You can take the same approach to displaying videos and images in your app. With the Video and Image column types, you can easily add a video or image to be displayed in any view of your app. Select the dropdown for the column type for that particular column and choose Image or Video.
You can also use a Show column type to display a video, particularly in a form view. You can learn how to do this with other types of content as well. It is also possible to add Show columns to other view types besides forms.
For both videos and images, you need to use a URL that is hosted on a webpage somewhere. This means that Google Drive links will not work.
Check out this video for an explanation of how to add different types of content to your forms using Show columns: